A. A common misconception is that only the main entrance to the home requires a mezuzah. Of course, it is better to have one mezuzah on the front door than no mezuzos, and if you only have one mezuzah, it should be placed on the home’s main entrance. However, to properly fulfill the mitzvah, every room in the house or office excluding a bathroom or shower room should have its own mezuzah.All rooms that are more than four cubits long and four cubits wide — approximately 6.5 feet by 6.5 feet (or its equivalent of 37 square feet) are required to have a mezuzah — as long as they have a full “doorway.” A blessing is not recited, however, if the room does not extend at least 6.5 feet in each direction.A doorway that requires a mezuzah is only one that has two doorposts and a lintel connecting the doorposts on top. If these conditions do not exist, a competent Rabbi should be consulted to determine whether or not that entryway requires a mezuzah.Garage doors, boiler rooms, attics, outdoor sheds, or crawl spaces require mezuzos provided that they comply with the required measurements (approximately 37 square feet). The doorposts themselves must be at least 10 handbreadths high (approximately 32 inches).An attic also requires a mezuzah unless it is entered via a “trapdoor” (a horizontal opening in the floor rather than a vertical opening in a wall).There is a difference of opinion by porches or sun porches some autorities hold the mezuzah is to be placed on the right side relative to a person entering the house, others hold it is to be placed on the right side relative to a person going out onto the porch, if you have a porch or a sun room a competent Rabbi should be consulted.A mezuzah needs to be placed at your workplace, in addition to private places of residence, however mezuzos should be affixed in businesses and stores without a blessing.If you’re working for a non-Jew and you are renting space from him, a mezuzah should be affixed on your office door without a blessing. However, if you are not renting the space, and there is the possibility that your office space could be relocated, then you would be exempt from affixing a mezuzah.If you have a non-Jewish live-in maid, you are required to put up a Mezuzah providing that upon your discretion, her room may be changed to another location in the house at any given time.Unused doors that are sealed closed (doors actually nailed to the door frame) are exempt from mezuzos. An entrance that is blocked by furniture or a door that is usually kept locked requires a mezuzah.Entrances of garages, storage rooms, doorways or archways that have no actual doors, or a room whose width is less than four cubits, but the total area is at least sixteen cubits square. (i.e. 2 by 9.5 cubits or 1.5 by 12.5 cubits). The blessing should be recited whilst first affixing a Mezuzah to a doorway that does require a blessing. The remaining Mezuzos are placed in the other archways, etc.The Mezuzah is affixed on the right-hand side of the door as you enter the room. It should be placed at a slight angle, with the top of the Mezuzah pointing toward the inside of the room and the bottom pointing toward the outside.The proper place for the Mezuzah is at the bottom of the top third of the doorway. In other words, measure the height of the doorway and divide by three; then align the bottom of the Mezuzah with the point two-thirds of the way up the doorpost. In most homes, the doorways are approximately 78 inches high, so the bottom of your Mezuzah should be no lower than 52 inches from the floor.If your doorway is much higher (say 90 inches or higher), affix the Mezuzah at shoulder height, even if this is lower than the upper third of the doorway. If the doorpost is very low, a rabbinical authority should be consulted in order to determine where the Mezuzah should be mounted.If the doorpost or archway is wider (thicker) than a handbreadth (approximately 3¼ inches), the Mezuzah should be mounted within the outermost handbreadth of the doorpost, rather than in the center. However, if there is a protrusion (such as a jamb) running along the height of the doorpost, some rabbinical authorities advise affixing the Mezuzah on the protrusion.The Right SideThere can be confusion as to which is the “right side” of the doorway. Is it the right as you enter a room or as you exit? And what about a doorway that is between two rooms (e.g., a doorway between a kitchen and dining room)?The basic rules are:

For the door at the entrance of the house, the right as you enter is always considered to be the right side.

Inside the house, if the doorway can be used as an entrance from either side, the right side is determined by how the door opens. Whichever room the door opens into is considered the primary room, and the Mezuzah is placed on the side that is on the right when entering that room.

The laws defining the terms “entrance” and “exit” are many and complex. If there is no door, if there is a swinging or sliding door, or if you are in doubt that you affixed the Mezuzah correctly, it is advisable to have a reliable rabbi visit your home to determine the correct location for the MezuzahYoung ChildrenWhen one has young children and they cannot reach the Mezuzah to kiss it, the Mezuzah should still not be placed lower than the top third of the doorway. Instead, you can lift your children up to the Mezuzah or keep a stool nearby so they can reach it on their own.When There Is No RoomThere are cases when it is physically impossible to affix the Mezuzah on the inside of the doorpost itself—for example, a swinging door interferes with the placement of the Mezuzah.In such a case, the preferred approach would be to make a groove that is less than a handbreadth deep, and place the Mezuzah in the groove.If that is not possible, then it would be permitted to affix the Mezuzah behind the door, provided it was placed on the doorpost.When necessary, it can be put on either the inner or outer side of the doorpost, as long as it is within about three inches from the opening of the doorway.You may also place the Mezuzah on the inner side of the doorpost if you are genuinely concerned that it will be stolen or defaced were it to be mounted on the actual doorpost.